/**
 *    Copyright (C) 2014 MongoDB Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kStorage

#include "mongo/platform/basic.h"

#include "mongo/db/storage/mmap_v1/data_file_sync.h"

#include "mongo/db/commands/server_status_metric.h"
#include "mongo/db/global_environment_experiment.h"
#include "mongo/db/instance.h"
#include "mongo/util/log.h"
#include "mongo/util/mmap.h"

namespace mongo {

    DataFileSync dataFileSync;

    DataFileSync::DataFileSync()
        : ServerStatusSection( "backgroundFlushing" ),
          _total_time( 0 ),
          _flushes( 0 ),
          _last() {

    }

    void DataFileSync::run() {
        Client::initThread( name().c_str() );

        if (storageGlobalParams.syncdelay == 0) {
            log() << "warning: --syncdelay 0 is not recommended and can have strange performance" << endl;
        }
        else if (storageGlobalParams.syncdelay == 1) {
            log() << "--syncdelay 1" << endl;
        }
        else if (storageGlobalParams.syncdelay != 60) {
            LOG(1) << "--syncdelay " << storageGlobalParams.syncdelay << endl;
        }
        int time_flushing = 0;
        while ( ! inShutdown() ) {
            _diaglog.flush();
            if (storageGlobalParams.syncdelay == 0) {
                // in case at some point we add an option to change at runtime
                sleepsecs(5);
                continue;
            }

            sleepmillis((long long) std::max(0.0, (storageGlobalParams.syncdelay * 1000) - time_flushing));

            if ( inShutdown() ) {
                // occasional issue trying to flush during shutdown when sleep interrupted
                break;
            }

            Date_t start = jsTime();
            StorageEngine* storageEngine = getGlobalEnvironment()->getGlobalStorageEngine();
            int numFiles = storageEngine->flushAllFiles( true );
            time_flushing = (int) (jsTime() - start);

            _flushed(time_flushing);

            if( logger::globalLogDomain()->shouldLog(logger::LogSeverity::Debug(1)) || time_flushing >= 10000 ) {
                log() << "flushing mmaps took " << time_flushing << "ms " << " for " << numFiles << " files" << endl;
            }
        }
    }

    BSONObj DataFileSync::generateSection(const BSONElement& configElement) const {
        BSONObjBuilder b;
        b.appendNumber( "flushes" , _flushes );
        b.appendNumber( "total_ms" , _total_time );
        b.appendNumber( "average_ms" , (_flushes ? (_total_time / double(_flushes)) : 0.0) );
        b.appendNumber( "last_ms" , _last_time );
        b.append("last_finished", _last);
        return b.obj();
    }

    void DataFileSync::_flushed(int ms) {
        _flushes++;
        _total_time += ms;
        _last_time = ms;
        _last = jsTime();
    }


    class MemJournalServerStatusMetric : public ServerStatusMetric {
    public:
        MemJournalServerStatusMetric() : ServerStatusMetric(".mem.mapped") {}
        virtual void appendAtLeaf( BSONObjBuilder& b ) const {
            int m = static_cast<int>(MemoryMappedFile::totalMappedLength() / ( 1024 * 1024 ));
            b.appendNumber( "mapped" , m );

            if (storageGlobalParams.dur) {
                m *= 2;
                b.appendNumber( "mappedWithJournal" , m );
            }

        }

    } memJournalServerStatusMetric;
}
